Multiple Autonomous Underwater Vehicle (AUV) System

ABSTRACT

Multiple autonomous underwater vehicles (AUVs) are operated by a single host surface vehicle (HSV) by configuring the AUVs with intermediate nodes (such as unmanned surface vehicles (USVs)) so as to allow the HSV to manage multiple AUVs. The intermediate nodes act as a relay for communications between the HSV and the AUVs allowing the HSV to scale to higher numbers of vehicles thus simultaneously operating the entire fleet of AUVs. The AUVs may provide underwater mapping data.

RELATED APPLICATIONS

This application is a continuation of PCT/US2017/060247, filed Nov. 6,2017, which claims the benefit of U.S. Provisional Patent ApplicationNo. 62/518,560, filed Jun. 12, 2017, the entire contents of both ofwhich are hereby fully incorporated herein by reference for allpurposes.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

FIELD OF THE INVENTION

This invention relates generally to underwater exploration, and, moreparticularly to multiple autonomous underwater vehicle (AUV) systems,methods, and devices for underwater exploration.

BACKGROUND

To-date, only about five percent of the world's oceans has been mappedwith high-resolution acoustics. One reason for this is the high cost ofcurrent mapping technologies and systems. As shown in FIG. 1,conventional mapping systems 100 typically use a combination of a hostplatform 102 and an underwater sensor deployment platform 104. In theexample depicted, the host platform 102 may be a host surface vessel(HSV) (e.g., a surface ship), and the underwater sensor deploymentplatform 104 may be an autonomous underwater vehicle (AUV) (e.g., asubmersible). The host surface vessel 102 typically deploys the AUV 104and travels along with it as the AUV scans the ocean floor. The hostsurface vessel 102 communicates with the AUV to provide navigational andmission command information and to receive positional, telemetry andmapping data, either in real time or recorded data upon recovery of theAUV 104.

The host surface vessel 102 is typically a large sea vessel equipped forexploration with a wide variety of high-tech sensors, data analysissystems, navigation and communications systems, mission planning andcontrol systems and software, GPS, as well as other equipment andsystems. In this way, the host surface vessel 102 may perform as thehost platform for planning, deploying, controlling, maintaining andanalyzing the mission. A typical crew of a conventional host surfacevessel may include fifty or more personnel, including officers,crewmembers, mission support staff and scientists. As such, the cost todevelop, build, man and operate such a ship is high.

AUVs 104 have become the underwater sensor deployment platform ofchoice. An AUV 104 is typically an underwater submersible vehicleequipped with a large array of sensors, cameras,front/side/bottom-looking sonars, contour profilers, echo sounders,navigation and communications systems and other equipment for datagathering, mapping, and communicating with the host platform 102. An AUV104 may have the ability to follow the bottom terrain contour of theocean and/or to maintain a fixed depth for consistent data gathering.However, these submersibles may be costly to develop, build and operate.

Host surface vessels 102 and AUVs 104 typically communicate usingacoustics (RF is highly attenuated through water and cannot be used).However, underwater acoustic communication with underwater vehicles isrange-limited by various factors including the frequency of thecommunications channel, the sound source level of the equipment, and thebackground noise level of the operating environment. The factors requirethat the surface transducer (of the host platform 102, for example) andthe submersible's transducer be within a nominally short range. Further,as the sensors aboard the AUVs 104 are both active and passive, thereshould preferably be some measure of range offset between the vehiclesin order to avoid interference between platforms and sensors.

For these reasons, conventional underwater mapping systems have requiredthe pairing of one host platform 102 (HSV) with a single underwatersensor deployment platform (AUV 104).

It is also important to note that the data gathered by an AUV 104 sensorplatform operating near the sea floor may be limited by the sensors'range of operation. In the example as depicted in FIG. 1, atypical/nominal Side Scan Sonar transducer (SSS—the primary mappingsensor) operated from the AUV 104 may function in the range of 75 kHzwith an average footprint of 1 km per channel (i.e., per side of thevehicle). Thus, for operation on both sides of the AUV 104, a totalcombined scan footprint swath 106 may be 2 km. Accordingly, to map aunit area using a one-HSV-to-one-AUV concept of operation, the HSV/AUVpair must travel back and forth through a grid along a narrow path only2 km wide.

Given the high cost to develop, build, operate and maintain each ofthese vehicles, it can be seen that the above concept of operation(pairing a single HSV with a single AUV) is inefficient.

It is desirable, and an object of this invention, to provide a moreefficient way of performing underwater scanning operations.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, and characteristics of the present inventionas well as the methods of operation and functions of the relatedelements of structure, and the combination of parts and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification.

FIG. 1 is a front view of a conventional surface host vehicle configuredwith a single autonomous underwater vehicle;

FIGS. 2-4 depict aspects of underwater scanning systems according toexemplary embodiments hereof;

FIGS. 5-7 depict aspects of exemplary search regimes according toexemplary embodiments hereof;

FIGS. 8-12 are views of a launch and recover system according toexemplary embodiments hereof;

FIGS. 13-14 show views of an exemplary unmanned surface vehicle; and

FIGS. 15-16 show views of an exemplary autonomous underwater vehicle.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTSGlossary and Abbreviations

As used herein, unless used otherwise, the following terms orabbreviations have the following meanings:

-   AC means Alternating Current-   ACOMM means Acoustic Communications-   ACS means Acoustic Communication System-   AIS means Automatic Identification System-   AMP means Amperage (i.e., the strength of an electric current in    amperes)-   APS means Acoustic Positioning System-   ATS means Automatic Transfer Switch-   AUV means Autonomous Underwater Vehicle-   COTS means Commercial Off The Shelf-   CTD means Conductivity-Temperature-Depth-   dB means Decibel-   DC means Direct Current-   DVL means Doppler Velocity Log-   FLIR means Forward-Looking Infrared-   GFCI means Ground Fault Circuit Interrupt-   GIS means Geographic Information Systems-   GNSS means Global Navigation Satellite System, and is a generic term    for satellite navigation systems that provide autonomous geo-spatial    positioning with global coverage. This term includes, e.g., the GPS,    GLONASS, Galileo, Beidou, and other regional systems.-   GPS means Global Positioning System-   GUI means Graphical User Interface-   HiPAP means Hi-Precision Acoustic Positioning (Kongsberg trademark)-   HMI means Human-Machine Interface-   HSV means Host Surface Vessel-   HVAC means Heating, Ventilation and Air Conditioning-   IHO means International Hydrographic Organization-   IMO means International Maritime Organization-   IN means Intermediate Node-   IP means Internet Protocol-   ISO means International Organization for Standardization-   ITA means International Trade Administration-   kHz/Hz means Kilohertz/Hertz (cycles per second)-   L&R means Launch and Recovery-   MBES means Multi-beam Echo Sounder-   mbs means megabits per second-   MILSPEC means US Military Specification-   MSW means Meters of Sea Water-   MPS means Mission Planning Software-   nm means Nautical Miles-   PLC means Programmable Logic Controller-   R/C means Remote Control-   RF means Radio Frequency-   SBP means Sub-Bottom Profiler-   SS5-   means Sea State 5-   SSS means Side Scan Sonar-   UPS means Uninterruptable Power Supply-   USBL means Ultra-Short Base Line-   USV means Unmanned Surface Vehicle-   VSAT means Very Small Aperture Terminal

A “mechanism” refers to any device(s), process(es), routine(s),service(s), or combination thereof. A mechanism may be implemented inhardware, software, firmware, using a special-purpose device, or anycombination thereof. A mechanism may be integrated into a single deviceor it may be distributed over multiple devices. The various componentsof a mechanism may be co-located or distributed. The mechanism may beformed from other mechanisms. In general, as used herein, the term“mechanism” may thus be considered to be shorthand for the termdevice(s) and/or process(es) and/or service(s).

As used herein, the term “underwater exploration” means, withoutlimitation, collection, gathering, generation, and/or determination ofany data relating to or based upon objects and/or conditions at leastpartially underwater. The term “underwater” may refer to any body ofwater including seas, oceans, and/or lakes (manmade or otherwise). Theinvention is not limited by the nature of the data collected, by whatthe data represent, or by the manner in which the data are subsequentlyused.

Overview

Recognizing the problems with prior conventional underwater (e.g.,subsea) mapping systems, the inventors realized various solutions,described herein. As will be apparent, the disclosed systems providesubstantial reduction in mapping cost per unit area by significantlyincreasing the area coverage per unit time. According to exemplaryembodiments hereof, multiple autonomous underwater vehicles (AUVs) mayoperate simultaneously with a single host platform (HSV). This isaccomplished using one or more unmanned surface vehicles (USVs) persingle host platform (HSV), with the USVs simultaneously operating asintermediate nodes (INs) between the HSV and multiple AUVs.

As depicted in FIG. 2, an underwater mapping system 200 according toexemplary embodiments hereof may comprise at least one host platform202, one or more intermediate nodes (INs) 204-1, 204-2, . . .(collectively and individually 204) and one or more underwater sensordeployment platforms 206-1, 206-2, . . . (collectively and individually206). In the example shown, host platform 202 may include a single hostsurface vehicle (HSV) as the host platform 202. The intermediate nodes204 may be or comprise one or more unmanned surface vehicles (USVs). Theunderwater sensor deployment platforms 206 may be or comprise one ormore autonomous underwater vehicles (AUVs). The USVs 204 may beautonomous or semi- autonomous. The USVs 204 may be surface ships orother types of surface structures (e.g., buoys), and the AUVs 206 aresubmersible vehicles.

Communication between the host platform 202 (e.g., HSV) and theintermediate nodes 204 (e.g., USVs) is preferably wireless. As shown bythe dot-dash lines 208 in FIG. 2, the host platform (HSV) 202 maycommunicate wirelessly with at least one intermediate node (IN) 204 viaa form of two-way transmitted communication signals, using one or moreof RF, microwave, IP-based radio, optical, and/or other types ofcommunication signals. As should be appreciated, a particular system 200may use multiple types of communication between the host platform andthe various intermediate nodes. There is no need or requirement for thesame system to be used by the host platform (HSV) 202 to communicatewith each intermediate node.

In this way, host platform 202 may provide real time mission control,navigational instructions and other information to each intermediatenode 204, while at the same time receiving data (e.g., navigational,telemetry and mission data) from each intermediate node 204. Eachintermediate node 204 preferably has a unique identifier such as aserial number that may be referenced by the communication signals suchthat the host platform 202 may specifically identify and communicatewith each individual intermediate node 204 as required. As noted above,the host platform 202 need not communicate with all intermediate node(s)204 via the same communications methods or protocols.

As used herein, a protocol refers to one or more procedures or systemsof rules, and a communication protocol refers to a system of one or moreprocedures and/or rules that allow two or more entities of acommunications system to transmit information via one or more kinds ofphysical media. The media may include, e.g., and without limitation,air, water, copper, optical fiber, electromagnetic waves, etc. As isknown, a communication protocol defines the rules syntax, semantics andsynchronization of communication and possible error recovery methods.Protocols may be implemented by hardware, software, or a combinationthereof. In general, a communications protocol is independent of themedia over/within which it may be used. For example, the medium mightinclude electromagnetic waves (e.g., light waves), sound waves (e.g.,over the air or in water).

Each intermediate node 204 may communicate with at least one underwatersensor deployment platform (AUV) 206 via, e.g., two-way acoustic and/oroptical communication transmissions (depicted by curved lines denoted210 in FIG. 2). In some preferred embodiments hereof, a singleintermediate node (e.g., USV) 204 may be paired with a single underwatersensor deployment platform (AUV) 206 as shown, but this pairing is notrequired for all embodiments. In this way, each intermediate node (e.g.,USV) 204 may transmit to its respective paired underwater sensordeployment platform(s) (AUV(s)) 206, mission control and/or navigationalinstructions that the intermediate node 204 may have received from hostplatform (HSV) 202. The intermediate node (e.g., USV) 204 may act as arelay, simply passing instructions directly to its respective pairedunderwater sensor deployment platform(s) (AUV(s)) 206. Alternatively (orin addition), the intermediate node (e.g., USV) 204 may process (orpre-process) information it receives from the host platform (HSV) 202,before passing instructions directly to its paired underwater sensordeployment platform(s) (AUV(s)) 206.

Each intermediate node (e.g., USV) 204 may receive communication signalsfrom its respective underwater sensor deployment platform(s) (AUV(s))206. In some embodiments, the intermediate node (e.g., USV) 204 maytransfer (or relay) the data received from a platform (AUV) 206 directlyto the host platform (HSV) 202. Alternatively (or in addition), anintermediate node (e.g., USV) 204 may store and/or process data receivedfrom a platform (AUV) 206. For example, if the data received from aplatform (AUV) 206 is telemetry data for the intermediate node (e.g.,USV) 204 to use to calculate information such as position and heading ofthe underwater sensor deployment platform (AUV) 206, the intermediatenode (e.g., USV) 204 may perform the required calculations and providethe necessary results back to the AUV so as to maintain positionalaccuracy in accordance with IHO standards. After performing somecalculations, an intermediate node (e.g., USV) 204 may communicate thisdata to the host platform (HSV) 202, e.g., for analysis. As such, it canbe seen that each intermediate node (e.g., USV) 204 may act as a relaybetween the host platform (HSV) 202 and its underwater sensor deploymentplatforms (AUVs) 206. Note too that an intermediate node (e.g., USV) 204may store data collected from its paired AUV 206 until such time as thedata can be reliably transmitted to the host platform (HSV) 202. In thismanner, an intermediate node (e.g., USV) 204 may provide redundantstorage of collected scan data.

The underwater sensor deployment platforms (e.g., AUVs) 206 arepreferably, but need not be, homogeneous.

Each underwater sensor deployment platform 206 (e.g., AUV) has acorresponding scan footprint swath (as described above with reference toFIG. 1). For example, as shown in FIG. 2, the AUV 206-1 has a scanfootprint swath defined by the line AB, and the adjacent AUV 206-2 has ascan footprint swath defined by the line CD. Preferably, in operation(for most scan protocols and/or search regimes), the scan footprintswath of adjacent AUVs should touch or at least partially overlap. Thus,as shown in the drawing in FIG. 2, swath AB overlaps swath CD.

In another example, as depicted in FIG. 3, an underwater mapping system300 according to exemplary embodiments hereof may comprise at least onehost platform 302, one or more intermediate nodes (INs) 304-1, 304-2, .. . (collectively and individually 304) and one or more underwatersensor deployment platforms 206-1, 206-2, . . . (collectively andindividually 206). In this example, the host platform 302 maycommunicate with at least one intermediate node 304 as depicted bydot-dash lines 306, and at least one intermediate node 304 maycommunicate with at least one other intermediate node 304, as depictedby dotted arrowed lines 308. In this way, intermediate nodes 304 mayrelay information to each other from the host platform 302. The hostplatform 302 may identify each intermediate node 304 by its uniqueidentifier and communicate with specific intermediate nodes 304 asneeded. These intermediate nodes 304 may in turn identify otherintermediate nodes 304 by their identifiers and relay the host platformcommunications to them. The interaction between the intermediate nodes304 and the underwater sensor deployment platforms 206 may be the sameor similar as described in the example above in FIG. 2. In theseembodiments, the intermediate nodes may, in effect, form a surfacenetwork of nodes, and the host platform 302 can preferably communicatewith any intermediate node, either directly or via the network ofintermediate nodes.

Intermediate nodes may communicate with each other by transmittedcommunication signals, using one or more of RF, microwave, IP-basedradio, optical, and/or other types of communication signals.Communication between the intermediate nodes may, but need not, use thesame protocol/mechanisms as communication between the host platform andthe intermediate nodes.

It should be understood that one or more intermediate nodes may bepreprogrammed with mission control software and files such that theymay, upon deployment, include all or a portion of the mission controlinstructions for their respective underwater sensor deployment platforms206. In this way, intermediate nodes may communicate mission controlinstructions to their respective underwater sensor deployment platforms206 without having to receive information from the host platform.

FIGS. 2 and 3 depict exemplary system configurations (200, 300) with asingle host platform (HSV 202, 302), six intermediate nodes (INs) (USVs204, 304), and six underwater sensor deployment platforms (AUVs 206).Those of ordinary skill in the art will realize and appreciate, uponreading this description, that these example configurations are notlimiting, and that, in general, a host platform may use and interactwith more or fewer intermediate nodes and underwater sensor deploymentplatforms. In general, in a system according to exemplary embodimentshereof, one HSV uses one or more intermediate nodes (USV(s)), and eachUSV uses one or more AUVs.

Preferred systems have one HSV, multiple USVs, and multiple AUVs. Aparticular preferred system has one HSV, multiple USVs, with each USVpaired with a single corresponding AUV.

With these system architectures, underwater mapping systems 200, 300allow a single host platform 202, 302 to communicate simultaneously withmultiple underwater sensor deployment platforms 206 via multipleintermediate nodes (intermediate nodes) 204, 304. As shown in FIGS. 2and 3, the multiple intermediate node / underwater sensor deploymentplatform combinations may be deployed in formations that maysignificantly increase the scanning footprint or radius of the overallsystems 200, 300 as compared to conventional scanning system (e.g., FIG.1).

Using the examples above, where the side scan sonar (SSS) radius of asingle AUV 206-i is 1 km, resulting in a scan footprint of 2 km for thatAUV, the addition of another five AUVs 206 and six USVs in theformations and operational architectures depicted in FIG. 2 and FIG. 3(side-by-side configurations) may increase the simultaneous scanfootprint to 12 km, an increase of 600%. As noted above, in theside-by-side configurations, preferably the scan footprints of adjacentAUVs abut or slightly overlap, so that six AUVs, each with a scanfootprint of 2 km will have a total scan footprint of less than 12 km.In general, n AUVs, each with a scan footprint of p km may, in theside-by-side configurations, have a combined scan footprint of ≤n.p km.Note that these exemplary formations may be or comprise a linearside-to-side formation meant primarily for descriptive purposes. Thoseof ordinary skill in the art will appreciate and understand, uponreading this description, that different and/or other scan formationscan be used (see SEARCH REGIMES below).

The intermediate nodes may also include surface platforms other thanUSVs 204, 304 with controlled (albeit autonomous movement). For example,as shown in FIG. 4, intermediate nodes 404 may be or comprise USVs thatare floating buoys that may each have a substantially fixed (e.g.,anchored) location or may be drifting. In these embodiments, such anintermediate node 404 may communicate with an AUV 206 within the rangeof its acoustic communications system. The intermediate node 404 mayalso communicate with a host platform (for example, an HSV 402) or othertype of host platform.

An array of such buoyed intermediate nodes 404, at appropriately spacedintervals, may be configured so as to manage one or more AUVs 206 over alarger area by handing off the AUVs 206 from one intermediate node tothe next while still maintaining constant communications. In the exampleshown in FIG. 4, the AUV 206 is moving from left to right, in thedirection of the arrow. While in the range of a particular node (e.g.,node 404-1), the AUV communicates with that node. As the AUV moves outof the acoustic communications range of node 404-1, and into theacoustic communications range of node 404-2, it may be transferred tonode 404-2 for communication and control. The handoff/transfer may besimilar to cell phone hand-offs between cell towers. The intermediatenodes 404 may be deployed and placed into position, e.g., via an HSV,USV or air dropped. Note that the AUV 206 may also come intocommunications range of the HSV 402 and may be transferred to HSV 402for communication and control.

Such an array of intermediate nodes 404 may also be configured to relaycommunication signals from an HSV to a particular intermediate node404/AUV 206 combination within the array. For example, the HSV may senda signal to a first intermediate node 404 that may then relay the signalto another intermediate node 404. The intermediate nodes 404 maycontinue to relay the signal until it reaches the desired intermediatenode 404. In this way, the array of intermediate nodes 404 may extendthe range of the RF communications from the host platform 402 to thedesired intermediate node 404/AUV 206 combinations. Note that thiswireless (e.g., RF-RF) relay may also be airborne (manned or unmanned)or space-based.

As with the configuration in FIG. 2, the configuration described withrespect to FIG. 3 may also comprise a network of intermediate nodes incommunication with one or more AUVs.

In all of the embodiments described, the intermediate nodes may be orinclude manned surface vessels.

In some configurations, the host platform may, intentionally orotherwise, move out of communication range of some or all intermediatenodes. In such cases, the intermediate nodes preferably continue tooperate the underwater sensor deployment platforms (AUVs 206), to theextent possible. In such cases, the intermediate nodes preferablymaintain communication and control of the AUVs and maintain (store)information gathered by the AUVs.

If an intermediate node loses communication with its host platform forlonger than expected, it may put the corresponding AUV into a mode(e.g., a low-power mode) to allow for continued operation and/orrecovery when communication with the host platform returns.

Search Regimes

FIGS. 2 and 3 each depict a search regime that generally comprises alinear side-by-side formation of the multiple intermediatenodes/underwater sensor deployment platforms combinations on either sideof the host platform. Those formations are only examples, and those ofordinary skill in the art will realize and appreciate, upon reading thisdescription, that different and/or other formations may also be used.

For example, as depicted in FIG. 5, an HSV 502 may be configured withsix USV/AUV pairs, three pairs of USVs 504 and AUVs 506 on the left sideand three USV/AUV pairs on the right, with the USV/AUV pairs on eachside lined up sequentially front to back. Each USVs 504 and AUVs 506pair may occupy a generally square search area having a width and alength, for example, of nine nautical miles (nm). The HSV 502 may assumethe central position (as shown in the drawing), and the fleet may movealong the line of progression (depicted by arrowed line AA′). In thisway, the search box forms an 18 nm×27 nm total search box (made up ofsix 9 nm×9 nm squares). The entire search box may also travel in alinear fashion along the line of progression AA′ after the entire regionis scanned.

In this formation, a worst-case scenario (with regards to maximumdistance between the HSV 502 and the USVs 504) may occur when the AUV506 is in a far corner of its square and the HSV is in the oppositecorner. It may be preferable that radio links between the HSV 502 andthe USV 504 be of sufficient power/range to allow communications betweenthe vehicles in this worst case. Bandwidth may be calculated to ensurethat all data from the AUV's sensors are transmitted to HSV(s) 502.

Although this regime shows six squares, in a general case of thisconfiguration, the regions need not be square shaped, and the searchregime may cover six rectangular shaped regions. Furthermore, in ageneral case of this configuration, the regions need not be of the samesize. For example, it may be advantageous to have some regions be largerthan others to accommodate launch and recovery times for the USVs andAUVs. E.g., the USV/AUV pairs that are launched first may be able toscan a larger region.

FIG. 6 depicts a search regime with a “Line Abreast” formation. As shownin the drawing, the formation of paired USVs and AUVs 604, 606 may bearranged staggered diagonally, e.g., from left to right, out in front ofthe HSV 602.

This formation may have the HSV 602 following along the diagonal row ofmapping vessels while making full use of each AUV's survey areacapabilities. Note that the time spent in turning the fleet from the endof one survey line to the start of another may be wasted with othertypes of formations. However, this formation may be able to continuescanning during a turn, thereby optimizing underwater vehicle traveltime.

A theoretical optimum for minimizing vessel movement may be to have astationary HSV and all USVs fanning out in a radial fashion from the HSVthen turning around and coming back to the HSV. Once the vessels returnto the HSV, the entire fleet, including the HSV may move to a newmission location. This has the HSV at zero movement until repositioningand may conserve fuel and operational costs of the HSV by having the AUV/ USV pairs doing the traveling.

The search regime shown in FIG. 7 may involve the HSV (not shown)traveling a minimal distance with the scan vehicle pairs proceedingfrom/to a baseline that may optimize the drop-off/pick-up location.

In this search regime, the system is scanning an area between the linesXX′ and YY′ in the drawing in FIG. 7. The HSV (not shown) travels alonga center line AA′, launching and picking up USVs and AUVs at variouslocations (denoted 1, 2, 3, 4, and 5 on the line AA′). For this examplesearch regime the USV/AUV pairs are denoted S1/U1, S2/U2, S3/U3, S4/U4,S5/U5, S6/U6, S7/U7, and S8/U8.

This regime may operate as follows:

1. At Location 1 (start location)—launch S1/U1 and then S2/U2

2. HSV Proceed to Location 3

3. At Location 3—launch S3/U3, S4/U4, S5/U5 and S6/U6

4. HSV Proceed to Location 5

5. At Location 5—launch S7/U7 and then S8/U8

6. HSV Proceed to Location 2

7. Pick up S1/U1, S2/U2, S3/U3 and S4/U4

8. HSV Proceed to Location 4

9. Pick up S5/U5, S6/U6, S7/U7 and S8/U8

10. HSV Proceed to Location 5 which now becomes the next start Location1 and repeat the sequence.

In the above example, while the HSV is doing steps 2-6, HSV/AUV pairsS1/U1 and S2/U2 are scanning the area between locations 1 and 2 (boundedby the lines XX′ and YY′). Similarly, while the HSV is doing steps 4 to6, HSV/AUV pairs S3/U3 and S4/U4 are scanning the area between locations3 and 2 (bounded by the lines XX′ and YY′). Note that S1/U1 and S2/U2scan up/down, moving left to right (from location 1 to location 2),while S3/U3 and S4/U4 scan up down, moving right to left (from location3 to location 2). In this way, S1/U1, S2/U2, S3/U3 and S4/U4 terminatetheir scans at location 2 and can be picked up there (in Step 7).Similarly, S5/U5, S6/U6, S7/U7 and S8/U8 terminate their respectivescans at location 4 and can be picked up there (in Step 9).

At step 7, the HSV may have to wait a location 2 for S1/U1, S2/U2, S3/U3and S4/U4 to complete their respective scans and arrive at location 2.Similarly, at step 9, the HSV may have to wait at location 4 for S5/U5,S6/U6, S7/U7 and S8/U8 to complete their respective scans and arrive atlocation 4.

Note that the above example fleet formations are meant to demonstratethe benefits of underwater mapping systems according to exemplaryembodiments hereof, and should in no way limit the scope of theinvention. Those of ordinary skill in the art will appreciate andunderstand, upon reading this description, that different and/or otherfleet formations or combinations of fleet formations may be used.

Mission Planning Software (MPS)

The mission planning and fleet management is conducted via missionplanning software (MPS). The MPS may define and delineate the operationsareas to be scanned, and may then attempt to optimize the search areaper USV/AUV combination, based, e.g., upon a so-called “TravelingSalesman” model of area coverage. Note also that other vehicle routeoptimization algorithms may also be employed.

The software may run on one or more controllers such as a computers,servers, mainframes, or other type of controller, and may generallyinput mission goal criteria, determine resulting mission parameters,generate mission control files for each vehicle in the fleet, analyzemission data, generate mission data reports, and generally providefunctionality to plan, configure, control, maintain and generallyoperate the fleet for each mission. Note that the MPS may include one ormore different scripts, software programs, applications or other typesof software that may run individually or in combination across one ormore platforms.

According to exemplary embodiments hereof, the mission planning softwarepreferably includes mechanisms for at least some of: (1) graphicallydepicting a search/operations area, in vector format, via a GIS-basedsystem with sufficient data layers for mission planning purposes, (2)defining the operating parameters then optimizing the fleet operationsvia the “traveling salesman” type solution (or other), (3) generating afull mission plan in the AUV control system's file format for uploadingdirectly to the AUV control system, (4) generating a full mission planin the USV control system's file format for uploading directly to theUSV control system, (5) transmitting said mission plan to the USV/AUVcombinations as necessary during the mission, (6) generating andtransmitting system-wide situation reporting for easy and rapiddissemination of the system status in human-readable graphics format,and (7) simulating missions for both planning and training purposes.

Note that the mission planning software may be fully autonomous, may beoperated via manual control, or may be operated via a combination ofautonomous and/or manual controls.

In some exemplary embodiments, the system may react in real-time toUSV/AUV problems, changing the mission profiles for other pairs to covergaps. In embodiments, the system may transmit new or modifiedplans/profiles to all affected elements. In some exemplary embodiments,backup plans may be included along with an initial or primary plan (PlanA) when first loaded into system elements, making it easier tocommunicate a command or instruction to switch to an alternate or backupplan.

Overall System Operation

In one example, a multi-AUV system according to exemplary embodimentshereof may operate as follows:

-   -   1. The designated operations area to be mapped may first be        identified. The parameters may then be loaded into the mission        planning software for processing and computing optimal asset        deployment.    -   2. A mission plan may then be generated by the mission planning        software in appropriate AUV and USV control system file formats.        As noted above, alternate or backup plans may also be generated.    -   3. The mission plan may be uploaded to the AUV control systems        and the USV control systems in preparation of launching the        AUV/USV vehicle pair(s).    -   4. The USVs may be prepared and launched (e.g., by a slewing        davit launch and recovery system). A launched USV may stand by        off-board and await deployment of a paired AUV. The USV may be        operated, e.g., in remote or tele-operated control mode via a        hand controller with the operator maintaining line-of-sight with        the vehicle in the vicinity of the HSV.    -   5. The AUV may be prepared and launched. The AUV may be        controlled, e.g., via IEEE 802.11 Wi-Fi communications until an        “execute mission” instruction is given.    -   6. Once the AUV leaves the surface, control may be transferred        to the acoustic telemetry system aboard a USV. Alternatively,        the acoustic telemetry system aboard the HSV may be used for        communication with the AUV.    -   7. Tracking and telemetry may be maintained through the USVs' or        HSVs' acoustic communications system(s).    -   8. Primary communication with the USV may be maintained with        IP-based radios during normal operations.    -   9. For loss of primary communications between the USV and the        HSV, high bandwidth local RF control may be available. Lower        bandwidth communications/control between the USV and the HSV may        be provided via satellite network, e.g., Iridium, for back-up        communications.    -   10. Once the AUV acquires bottom lock with its acoustic tracking        Doppler Velocity Log (DVL), the vehicle may continue its planned        mission until a mission termination or abort instruction is        received for execution.    -   11. The SSS onboard the AUV may be used as the primary mapping        sensors.    -   12. Various other payload sensors may allow ambient parameters        to be measured for survey and mapping purposes. Among these        sensors are SSS, SBP, MBES, turbidity, CTD, magnetometer, laser        scanners, optical backscatter (i.e., digital stills camera with        strobe for lighting) as well as other types of sensors.    -   13. An AUV may also include a high-resolution digital camera or        (optionally) a laser scanner able to capture images (e.g., still        images and/or optic backscatter) of the bottom, optionally based        upon findings from other sensors.    -   14. Once the minimum reserve power level is reached, the vehicle        may either internally-generate a mission termination command,        receive a direct supervision for “return to surface” from the        operator station aboard the HSV, or some other onboard command        may be given to abort the mission and “return to surface.”    -   15. The USV may continue to shadow (i.e., follow or remain near        to) the AUV once it has returned to the surface, loitering while        the HSV moves into position for the recovery.    -   16. The AUV may be recovered for servicing, data offload and        reprogramming in preparation for the next mission.    -   17. The USV may also be recovered for maintenance and        preparations for the next mission.

Benefits

The benefits of underwater mapping systems disclosed herein aremultifold. As described above, it is easily understood that theoperation of multiple AUVs from a single host platform (HSV) viaintermediate nodes may drastically increase the area coverage per unittime, resulting in shorter missions, better utilization of high-costresources, and an overall mission cost reduction.

In addition to this primary benefit, other substantial benefits alsoexist. For example, the USV/AUV pairs may generally operate autonomouslyonce the mission commands have been implemented. This may allow for theremoval of the host vessel for a limited period for resupply ormaintenance, or to service other vehicles within the fleet whilemaintaining ongoing mapping operations.

The HSV's overall movement may be generally minimized by having theUSV/AUV combinations perform most of the movement while stillmaintaining constant (or near constant) communications with the HSV.This may save on fuel, maintenance, personnel, etc. for the HSV.

In addition, because the system is able to scan a wider underwater areain a shorter amount of time, it may take advantage of favorable weatherwindows of opportunity for continued maritime operations. Missions maybe completed faster with fewer interruptions, resulting in substantialoverall cost savings. In addition, this may allow for decreased costsrelative to vessel supported operations and decreased head count at seaalong with associated reduced Health, Safety and Environmental (HSE)risk.

It should also be noted that the use of robust and durable standardizedequipment may lead to a reduction in needed spares and faster repair andmaintenance of the equipment.

The system also allows for the changing of a mission plan in real timeand even the ability to eliminate the HSV altogether and instead managethe fleet from another host platform that may be located on-shore or inanother location.

In some cases, the system may support a handoff of USV/AUV pairs fromone HSV to another system (e.g., another HSV or a shore-based system).

Exemplary Technical Requirements

Aspects of embodiments of the host platform, the intermediate nodes(INs), and the underwater sensor deployment platforms will now bediscussed in further detail.

The entire fleet of vehicles used by an underwater mapping system (e.g.,200 in FIG. 2, 300 in FIG. 3) may be centrally commanded from the HSV202 (performing as a host platform). The fleet of vehicles may includeunmanned surface vehicles (performing as intermediate nodes 204), andautonomous underwater vehicles (performing as underwater sensordeployment platforms 206).

As stated above, the HSV 202 may typically be or comprise a large shipequipped with a wide variety of sensors, data analysis systems,navigation and communications systems, mission planning and controlsystems and software, GPS, as well as other equipment necessary toimplement, deploy, and generally manage underwater mapping system (e.g.,200 in FIG. 2, 300 in FIG. 3).

The HSV 202 preferably includes the launch and recovery systemsnecessary to deploy and recover the USVs 204 and AUVs 206. Examples ofthese launch and recovery systems are depicted in FIGS. 8-12. Accordingto exemplary embodiments hereof, these systems preferably include someor all of the following: (1) a means of launching and recoveringmultiple USVs and AUVs in sea conditions up to SS5; (2) a means ofsteadying each vehicle, while in the transition stage via a recovery orpainter line; (3) a davit system or the like for launching andrecovering of a fast response boat (e.g., for emergency operations); and(4) a means of remotely capturing a bullet-type latching system actuatedthrough the telemetry system of the USVs.

An HSV may also include operator stations that may be manned to control,e.g., navigation, telemetry, and general operation of the USVs and theAUVs. These stations may include control console GUIs that includepictorial graphics for human interpretation of the status of eachvehicle as well as each vehicle's current location. In general, the HSVis preferably properly equipped and manned to control, operate andmaintain all of the functionalities of the USVs and the AUVs as requiredby each mission.

In addition, according to exemplary embodiments of underwater mappingsystem hereof, the HSV may include a packet-switching IP radio networkthat preferably include some or all of the following:

(1) an RF (radio frequency) communication system with sufficient rangeto communicate with the USV fleet to the full anticipated separationbetween the HSV and the USVs; (2) sufficient bandwidth through thecommunication system to receive and process the data from of the variousassets; (3) sufficient beam coverage so as to allow two-way operation ofthe communication system through 360 degrees of HSV bearing to the offboard asset(s) (e.g., USV(s)), and (4) sufficient antenna “height ofeye” to allow for full range of communications during all hours withoutsurface ducting (this may include antenna extension via unmanned aerialvehicle, if necessary). As described above, the radio network may beused to provide two-way communications between the HSV and any othervessels in the fleet (for example, the USVs and the AUVs).

The intermediate nodes provide links between the host platform and thevarious underwater sensor deployment platforms. The USVs (performing asintermediate nodes) relay communications back and forth between the HSVand the AUVs, whereby the HSV may control each individual AUVsimultaneously.

USVs

A USV according to exemplary embodiments hereof may be a surface shipthat preferably includes some or all of: (1) a maritime system compliantto IMO requirements for unmanned maritime systems, (2) a payload andelectronics bay sufficient to accommodate the Acoustic Communication andPositioning System (ACOMM and APS) for its full range of operation, (3)a means of Launch and Recovery (L&R) in all weather conditions up to SeaState Five (SS5) in day/night operation, (4) multiple means ofuninterrupted communications with the HSV, and (5) sufficient onboardintelligence to shadow the AUVs along with reacquisition algorithmshould maneuvering be required for surface collision avoidance.

With reference to FIGS. 13 and 14, an exemplary USV may have thefollowing specifications:

-   -   1. Length: 7.22 m (23.8 ft.)    -   2. Draft: 1.9 m (6 ft. 2 in) (USBL Hydrophone Extension Pole        Deployed)    -   3. Height Overall: Approximately 2.5 m-8 ft. 2 in    -   4. Weight: 3,630 kg (8,000 lbs.) (Full Fuel & Payload)    -   5. Propulsion System: Twin Yanmar 4vJH45 (45 hp) Diesel Twin        Fixed Propellers    -   6. Fuel Capacity: 700 L (185 U.S. gal)    -   7. Speed: 2 knots-10 knots    -   8. Endurance: 180 h @ 4 knots

As should be appreciated, these specifications represent a typical orexemplary USV, and that other USVs with other general specifications maybe used.

As stated above, multiple (e.g., two or more) fully or partiallyautonomous USVs may be included with an underwater mapping systemaccording to exemplary embodiments hereof. Once deployed, the USVs maysafely/accurately operate in harsh marine conditions up to and includingrough Sea State Five (SS5) seas (as described in Beaufort Scale). Theprimary purpose of these USVs is to track and communicate with at leastone AUV per USV and to relay communications back and forth to an HSV. Anadditional main function of the USV is to provide to the AUV periodichigh-accuracy surface-based positional information based upon satellitepositioning. Tracking may be accomplished, e.g., via a retractableUltra-Short Base Line (USBL) preferably through hull center that mayinclude a transceiver that may communicate with a transponder that maybe included with AUV. Note that this may also be accomplished using adifferent type of acoustic transducer, and that a differentinterchangeable head may be installed for deeper water operations (i.e.,below 5000 m). A computer, or “topside unit” may be used to calculate aposition from the ranges and bearings measured by the transceiver.

Piloting requirements for L&R and normal operations may be a combinationof fully autonomous and human-assisted modes. In addition, manualoverride of autonomous operations, converting to human intervention andback to fully autonomous, is preferably also provided.

Stability requirement may be inherently mandated for a USV to hostthrough-water tracking of AUVs from the surface to at least 6,000 MSW(˜19,685 feet).

Roll and pitch of the USV are preferably constrained to less than 22.5degrees either side of its centerline in either direction (roll orpitch). This is due to a transducer's/hydrophone's tracking cone beingnominally 45 degrees in diameter. Note that the actual roll/pitchlimitation requirements will be dependent upon the USV hydrophone'sspecifications and the requirements will be adjusted to conform to thehydrophone head's capabilities.

Deployment/Recovery from HSV in up to and including SS5 conditionssafely, efficiently, with consistent repeatability may be required. Inaddition, a USV may have primary and secondary systems for allcomponents; communications, navigation, propulsion, power generation,etc.

Propulsion system of the USV (Primary/Secondary) are preferably able tosupport prolonged operations (e.g., greater than 72 hours at 4-knots).The propulsion system may be capable of supporting short periods ofoperations (1-hour) at maximum operating speed greater than 10-knots. Ahigher operating speed may be used, e.g., to move the USV away from theHSV during launch, as well as to approach the HSV during recovery.Onboard fuel capacity preferably supports at least 96 hours ofcontinuous operations with a full mission package onboard and operating,without refueling, in SS5 conditions.

Environmental conditioning systems (Primary/Secondary) should be capableof maintaining environmental conditions (e.g., HVAC and humidity) withininterior spaces of the USV to support any entire critical electronicssuite installed. These systems preferably support worldwide operation(e.g., conditions of hot, cold, humid, arid, dusty/sandy, freezingconditions).

The USV may possess an electrical power generation system (Pri/Sec),auto transfer switch (ATS) and uninterruptable power supply (UPS).Electrical power generation may be sized to support the known/expectedentire electrical load with consideration for potential growth onelectrical load due to future added functionality and capabilities. Allpower may be run through the uninterruptable power supply (UPS) toensure clean, consistent, and conditioned power that may be afforded allonboard electrical components. UPS duration is preferably greater thansix hours (with all systems operating) to initiate mission abort(surface) command to any assigned AUV. Electrical power generation maybe required to support worldwide operating arena conditions (e.g.,conditions of hot, cold, humid, arid, dusty/sandy and/or freezing).

The ATS (auto transfer switch) may support incoming power from at leastthe (1) primary electrical power generation source, (2) secondaryelectrical power generation source, and (3) HSV 102 power (when ondeck). Note that the “on-deck” shore power requirement may require oneshore power cable per USV (with rated AMP capacity of shore power cable,with plug, to be sized to conform to the onboard power requirements).

Electrical/electronic communications (e.g., command & control,navigation, illumination) requirements (Primary/Secondary), along withthe critical requirements of the USV, may be sufficient to constantlymonitor the assigned AUV's location, as well as “on task” operations ofthe AUV. This may include the need to remain in constant communicationto ensure continual monitoring of command and control as well as healthand status of the physical condition of the AUV. The USV may monitorsome or all of: engine functions, electrical power generation functions,UPS status, radio status (i.e., signal strength), system bilge fill(preferably with at least two different sensor units), gyro-stabilizedpitch and roll system, status of air conditioners, fuel systems andother characteristics, components and/or elements of the AUV.

Communication

Those of ordinary skill in the art will realize and appreciate, uponreading this description, that a key point to consider when establishinga network is height of eye requirements on USVs and HSV along withelectronic transmission/reception (send (transmit) and receive) signalstrengths. Consideration should be given to ensure these systems(Primary/Secondary) are not interrupted, corrupted, or hacked. Exemplarycomponents may be as follows:

-   -   1. Mesh radios that provide network relaying to all USVs from/to        the HSV.    -   2. Serial data / IP radios to ensure encryption and improve        distance/retransmit rate. This may require a calculation of the        bandwidth required.    -   3. Very Small Aperture Terminal system (VSAT) with 1.5 MBs        capability up, and 0.75 MBs capability down. This may greatly        improve distance and decrease the latency period of the data.        This may also require calculation of required bandwidth.    -   4. Transmitter and/or receiver capable of communicating with        satellites, e.g.,

Iridium.

-   -   5. VHF radio (Marine band) voice only that may be used when        boats are physically manned in real time.    -   6. Automatic Identification System (AIS)    -   7. GNSS (preferably Survey Grade DGNSS to incorporate        differential GPS signals as well as differential GLONASS)    -   8. IMU    -   9. 4G radar    -   10. FLIR and Daylight cameras    -   11. Depth log    -   12. Gyro Stabilized Magnetic Compass and/or GNSS Altitude System

In addition, consideration may be made for personnel manningrequirements to support USV's pre/post operations checks, andpreventative maintenance, including diesel marine mechanic,electrical/electronic/wireless communications tech and other types ofpersonnel.

An exemplary USV may have sensors for at least some of these parameters:Master Caution, Engine Oil Temperature/Pressure, Onboard Fuel Level,Multiple Fire Alarm Sensors in Select Strategic Locations, CabinTemperature/Humidity, Engine Compartment Temperature/Humidity, BatteryStatus, Amp Meter Output (Charge/Discharge), Tachometer for all engines,Drive Transmission Status (Fwd/Neut/Rev), Rudder Angle Indication,Compass Heading, Gyro heading off of HiPAP, Vessel Orientation, GPS/AIS,Forward Looking Infrared (FLIR) Camera, Radar, Nav Light Status, USBLpole status indicator, Bilge Alarm Status, and Low resolution / framerate camera in engine room and bridge.

Note that the mast height of the USV should preferably be sufficient todrive line of sight Radio Frequency (RF) communications (Comms) duringsea state five (SS5) conditions to at least the maximum SS5 wave height.

In addition, all sensors are preferably easily viewable via pictorialpresentation on a Graphical User Interface (GUI) displayed (Analog orDigital Gauge) on the operator's console aboard the HSV. Operator'scontrol console should possess both GUI for payload sensors as well asUSV status and control. Also, USV operator's control console may allowfor tele-operation of USV via manual joystick or other Human-MachineInterface (HMI) device. This input device may be manual (i.e., joystickor mission input into Operator Console [i.e., input requiredheading—speed—avoidance distance radius—Input mission plan—etc.]).

It may also be preferable that payload sensors/systems have minimalthroughput degradation of functionality other than latency oftransmission. Payload on AUV may be dependent on AUV depth and latency(also limited at maximum depth).

A separate portable hand controller capable of holding up to harshmarine offshore environment (rain, splash, immersion, and shock/impactresistant) may also be provided for Remote Control (R/C) of USV fromdeck for L&R of USV from HSV. This may include Wi-Fi communication /control systems on both HSV and USV. Note that the remote deckcontroller could be based upon a standard tablet computer or similarCOTS device.

Each USV may also possess control modes for three different functions:(a) logic driven local onboard control, (b) USV tele-operated or R/Ccontrol override, and (c) USV onboard manual control. The onboardlogic-driven control may allow for constant tracking of AUV with no morethan the lesser of a five degree radius offset from the vertical or 100meters radius from the vertical (from the AUV's position/perspective).This variable may be inputted rather than hard coded to allow foroperator adjustment.

The onboard control software may allow for loss of tracking as well asconsideration for sea state and wind / wave direction relative to thedirection for survey travel. In this case, an option may be to haveKalman Filter with mission plan used to follow the AUV (e.g., the USVstops and commences hovering circling around last known position of AUVuntil HSV gets there and takes control of USV and positions it on top ofAUV).

The USV control console GUI may have pictorial graphics for easy humaninterpretation of both positional situation and AUV/USV status. This maybe used so that all USVs and AUVs are on an active electronic chart fortracking both from the operator's console as well as from the HSVbridge.

The USV may have sufficient vessel stability as to keep the acousticacceptance cone oriented towards the AUV acoustic communications (ACOMM)transducer so as to allow constant communications. To accomplish this, agyro-stabilized system may be used to aid in the reduction of roll.

The USV hydrophone pole may be retractable during deployment andrecovery of the vessel to avoid damage during L&R of the USV to/from theHSV.

In some cases, it may be preferable for the USV to have a line of sightRF communications capability to worst-case scenario of 32 nm.

The USV fleet communications system may be via IP-based “meshed” radiosystem to allow for multiple communications paths and a robustdata/video radio network. Those of ordinary skill in the art willrealize and appreciate, upon reading this description, that calculationsof bandwidth will determine the degree to which data and video may besupported.

As to the vessel structure, the size of the USV hull may be sufficientto allow for stable and extended operation in open seas up to SS5 andthe electronics area within the USV may allow for controlled temperatureand humidity so as to remain within the nominal tolerances of theequipment manufacturers' specifications. Note that the command andcontrol system may be able to control USV hold temperature and humidity.

It should be noted that the USV may have enough human occupancyaccommodations to safely allow for emergency boarding and assumption ofmanual control of the USV for a period of at least one hour. The USVoperator cockpit may have a manual override device for hot swapping fromprogrammable logic controller (PLC) control to onboard manual control.

Each USV may have dual drive engines for redundancy and be of sufficientsize to drive the USV at least 10 knots through the water on only oneengine. The required onboard electronics package may be driven byPrimary/Secondary battery banks that may be recharged via drive enginecharger and/or by other means. The battery bank (if used) may be ofsufficient size to drive all electronics and vessel control for sixhours after total loss of charging source. The USV may have sufficientendurance to drive the USV (with all electronics engaged) for at least100 hours without refueling or servicing.

The USV hull may possess a hard point bollard on the bow and stern fortowing or being towed by other USVs via manual control. The hull may berobust enough (with sufficient bump and guard railing/protectors) toallow for non-precision control through off-board remote console. TheUSV hull may also allow for easy servicing while maintaining a minimalenvironmental impact risk. This may specifically include drip-lessrefueling mechanisms and minimal sea exposure to greases and lubricants.

The USV engine may be a marine diesel design with either inboard orinboard/outboard propeller-based drive mechanism (i.e., non-“jet drive”)or with other types of propulsion mechanisms or systems.

The USV may have a waterproof “Shore Power” receptacle for remotepowering [i.e., HSV power] of the USV while it may be on deck and beingserviced. This may allow for continuous powering of the USV subsystemsalong with maintenance of cabin environmental parameters.

The USV may also have a water-proof computer patch panel mounted onoutside of cabin so computers may be interfaced to monitorsystems—sensors etc. while on deck of the HSV.

The USV may have the ability to right itself after capsizing. If this isinitiated there may be an automatic shutdown of all onboard engines, andthe automatic shutdown system may be field-adjustable to engage oncecertain nominal hull orientations are exceeded.

It may be preferable that the USV mast height be sufficient to maintainline of sight with the antenna array on the HSV as well as other USVantennas within the meshed network to the maximum anticipated distanceoffset. The USV mast height may support the installation of a satellitecommunications dish.

The USV may also possess sufficient navigational shapes and lighting tocomply with IMO regulations for class / type specific operations duringall hours of the day. The USV mast may be able to support display ofrequisite navigational day shapes. The USV mast may have the capabilityof being stowed for secure handing during L&R as well as duringtransportation.

The USV onboard Program Logic Controller (PLC) may have at least onebackup for redundancy.

The USV may have at least three paths of communications with the HSV(e.g., direct RF, RF through IP “meshed” network, or through VSAT LargeBandwidth and Iridium Satellite Communications). Note that Iridium maybe used for minimum commands and may not be used for normal operation.

The USV may also have a sufficient control algorithm to allow forminimal wear and tear on control surfaces as well as engine /transmission mechanisms. The engine may be sized for optimal performance/ endurance at the standard operations speed of four to ten knots.

All electronics and mechanisms within the USV hull may be secured inshock-resistant mounts to MILSPEC (MIL-S-901D) and all equipment mountedon the USV hull may be secured to allow for a full 360 degree rollshould the vessel capsize.

The radar and FLIR camera may be displayed with sufficient resolution onthe USV operator's console to recognize at-sea obstacles in sufficienttime to take over manual remote tele-operated control so as to avoid theobstacle.

The USV hydrophone pole extension mechanism may have a failure mode tothe “retracted” position so as to avoid possible damage during L&R withfull power loss to the USV.

The USV hull may be designed for mating/latching with a separate L&Rdavit system, and the USV may be sized (height and width) forover-the-road transport within current legal limits of the USA &international highway laws. Note that the USV may likely require groundtransport at times, e.g., via semi-tractor trailer rigs and may be wideor oversized (height/width limits compliant). The USV may come withindividual metal flat racks for ground transportation that may have aconformal cradle for accommodating the hull. This cradle may be capableof fitting on to any ISO standard container chassis for easytransportation via common carrier. This way, the USV may be transportedvia road, sea or air.

For some environments, it may be preferable that all items within theUSV system possess no natural wood and a minimal amount of “man-made”wood. This may be to mitigate/avoid wood-borne pest control restrictionsfor international customs/import & export requirements.

The USV may also have a small locker for an adequate anchor (with chain)should power loss be sustained during manned operations. Note that thelength of line and chain size/weight of anchor may be appropriate forthe size and class of USV. The bow bulwarks may be equipped with atowline fairlead for channeling of a towline during towing operations.

It may also be preferable for the USV hull to have adequate cathodicprotection, and that the entire onboard electrical system has adequateground fault monitoring and protection.

The temperature controlled area of the USV hull area may be insulated toconserve energy required for temperature/humidity control. There mayalso be a fire suppression system within the engine compartment. Notethat HALON, FM 25 or FE 25/FE13 may be implemented based upon theanticipated fire suppression mode.

In addition, all USV onboard AC power may be standardized at 50 Hz powerat a nominal 230 VAC (European Standard). The input power to the USV mayallow for variable standards (110/220/440 at 50/60 Hz) in order toaccommodate varying vessels of opportunity. In addition, power plugs maybe standardized for European plug types—US Department of CommerceInternational Trade Administration (ITA) grounded plug types C/E/F.

There may also be two independent electrical power systems—one DC foroperation while deployed and one AC while operating via HSV power.Adequate AC outlets may be provided for maintenance purposes with aminimum number of five AC outlets aboard the USV. Note that allelectrical outlets may be grounded via GFCI protection.

The USV may have the ability to both navigate via following the AUV aswell as for waypoint navigation.

The USBL pole mounting plate may be swappable between the APS heads. Inaddition, it may be preferable for the USBL pole to be of sufficientlength to allow the hydrophone head to protrude below the level of thekeel and be sufficiently away from vessel self-generated noise for allnominal tracking operations. Note that an Acoustic Noise test may beperformed to determine noise produced by onboard machinery (engines &power gen sets, and cavitations) to assess dB noise level produced inorder to calculate/determine USBL pole length requirements. Also, allmachinery used onboard the USV may be shock-mounted so as to minimizethe propagation of USV vessel self-noise in support of acousticoperations.

Some USV controls may require some type of remote actuation in order toproperly control the USV. These controls may include: (1) DriveTransmission (Forward/Neutral/Reverse), (2) Engine Throttle Position,(3) USBL Pole Position (and locking), (4) Helm Angle, (5) HVAC andEnvironmental System (Temperature and Humidity), (6) Engine Start/Stop,(7) Engine Trim (Specifically, Drive Train Vertical Angle), (8) AntennaMast Suite Raise/Lower/Lock, (10) Deployment of a USV Bow RecoveryLine/Painter Line and other controls.

AUV

An AUV according to exemplary embodiments hereof preferably includes atleast some of: (1) means of mechanically propelling the vehicle alongthe operations area with positive control through its entire controlregime, (2) a movable steering mechanism for both pitch, yaw and roll soas to allow for varying degrees of operational freedom, (3) a Side ScanSonar (SSS) (e.g., EdgeTech 2205 with frequency 75/230/410 kHz) formapping the sea bottom of sonar targets via acoustic backscatter, (4) asub-bottom profiler (SBP) for measuring bottom type and consistency, (5)a digital color camera and/or laser scanner (e.g., CathX Ocean StillColor) for imaging the sea floor allowing for interlacing photos orgenerating three dimensional point cloud mapping, (6) aself-compensating magnetometer for sensing the ambient magnetic field(e.g., Ocean Floor Geophysics SCM), (7) a Multi Beam Echosounder (e.g.,Kongsberg Maritime EM 2040), (8) a Sub-Bottom Profiler (e.g., EdgeTech2-16 kHz), (9) a Conductivity/Temperature/Depth (e.g., SAIV or similarCTD sensor) sensor, (10) means of maintaining precise navigation andobstacle avoidance along the entire survey/mapping route, (11) means ofcommunicating with the surface via two-way acoustic communicationbetween the AUV and the surface transducer (for positioning andtelemetry), (12) a 3-axis gyro, magnetometer, accelerometer for sensingvehicle orientation, (13) a pressure-sensing depth gauge, (14) anAcoustic Positioning System (APS) with modem for vehicle location andremote communication, (15) an internal control system via software forvehicle diagnostics and systems control, (16) a 3-axis high-precisioninertial measurement unit for measuring acceleration in all axis ofoperation, (17) batteries for locomotion, sensor operation and control,(18) a strobe light (for recovery at surface), (19) sacrificialdeployment weights (concrete or other environmentally-friendlysubstance) for buoyancy control, (20) activated remote release as wellas manual drop weight release for dual means of recovery from the seabottom, (21) Radio Frequency, IEEE 802.11 WiFi and Iridium satellitecommunications capabilities with the vehicle while on the surface, (22)syntactic foam buoyancy (overall neutral buoyancy), (23) easy access tothe video and data capture storage device (e.g., a storage card), (24)batteries to be charged in housing/battery packs with housing/packseasily detachable from vehicle, (25) internal Image and Data Capture(Compact Flash or other high density media), and (27) other types ofcomponents, elements, instrumentation and capabilities that may berequired for the operation of the AUV.

Nominal AUV parameters are as follows—Dimensions: Length 6.2meters×Diameter 85 cm, Depth Rating: Maximum 6,000 meters/Minimum 5meters, Power Supply: Rechargeable and Swappable Lithium PolymerBatteries, Estimated Endurance: two Battery Packs per AUV (Primary andback up for quick change out) provide 48 Hours at 4 knots with SSS,MBES, SBP, Magnetometer and Camera operating 100% of the time.

As described above, the USV may communicate and track a paired AUV viaan Acoustic Positioning System (APS) to establish relative and absolutepositions of the AUV underwater. In the examples described above, theUSV/AUV pairs may use an Ultra Short Base Line (USBL) system todetermine the range and bearing of the AUV.

AUVs may collect underwater scanning data and send collected dataacoustically (through the water column) to a USV during missions usingthe acoustic positioning (USBL) (e.g., an HiPAP). The USV may thentransmit data/communicate back to the HSV using, e.g., the KongsbergMarine Broadband Radio (MBR) or similar COTS-based IP radio system. Thismay allow for real time monitoring of data while surveying.Communication back down to the AUV may also take place for mission planchanges such as direction and location.

In operation, an example sequence of events to determine the location ofAUV may be as follows:

-   -   1. The USV via the USBL system may emit a specific acoustic        pulse to query transponders that may be on the AUV that the        particular USV may be tracking.    -   2. The pulse may travel through the water and be detected by the        transponder on the AUV.    -   3. The transponder on the AUV may respond to the pulse with a        unique transponder acoustic pulse which may return through the        water back to the USBL.    -   4. The USBL array may detect the unique transponder signal and        determines the round trip acoustic travel time and phase delay        of the signal. It may then use this data to determine the        location of the AUV and relay this information to the HSV as        necessary. Telemetry data may also be received from the AUV and        relayed to the HSV as required. The USBL APS can then transmit        its positional information back to the AUV for updating its        positional fix.

Note that the sound speed at the USBL array may be used to calculate thereceived bearing of the unique transponder signal, and the average soundspeed of the surrounding water may be used to calculate the range of thetransponder. In addition, if refraction is included in the calculations,the sound speed profile of the surrounding water may be used tocalculate range and adjust the vertical bearing to the transponder.

As should be appreciated, because the APS uses acoustic technology, itis critical to accurately measure and determine the sound velocity. Asis well known, water density is affected by water temperature, pressure,and salinity. This density also directly affects the speed of soundtransmission in water. If an accurate round-trip time/speed can becalculated, the distance to a vehicle from a reference point can beascertained.

The simple formula R×T=D (rate×time=distance) may be used. The timefunction is measurable and the rate question is dependent upon themedium through which the sound travels (in this case water). The timingof the sound wave traveling across the surface USBL transducer arrayallows for a bearing and azimuth resolution to the underwater AUV.

Given these requirements, an Acoustic Positioning System (APS) accordingto exemplary embodiments hereof preferably includes: (1) a hydrophoneonboard the USV (via an UBSL for example) for interrogating a underwaterbeacon (for range and bearing resolution), (2) multiple transducerelements (an array) within the hydrophone for resolving bearing andazimuth to the underwater target, (3) sufficient sound source level topropel the acoustic signal to/from the AUV with signal to noise ratiothat allows positive two-way communications between the AUV and the USV,(4) onboard USV processing power sufficient to accurately convert therange/bearing resolution to geographic coordinates, (5) an onboard USVinertial measurement unit to correct for movement of the surfaceplatform (i.e., the USV or HSV) due to sea state motion, and (6) anonboard USV GNSS (e.g., GPS) for resolving positional fix in ahigh-accuracy fashion.

A USV (operating as intermediate node) may be preferably positionedwithin the acoustic range of the AUV's transducers in order to maintainconstant and continual acoustic communications with the AUV (operatingas underwater sensor deployment platform). As shown in FIGS. 2 and 3,this position may be generally above the AUV. This allows the HSV (hostplatform) to manage multiple AUVs simultaneously via the multiple USVs.The upper theoretical limit of simultaneous operations is then onlyconstrained by the range and bandwidth limitations of the communicationssystems. While contact between the AUVs and the HSV vehicles ispreferably constant, those of ordinary skill in the art will realize andappreciate, upon reading this description, that some amount ofinterrupted contact may be acceptable in some implementations and/or forsome applications.

Telemetry data, mapping data and other types of data may also betransmitted by the AUV to the USV using acoustic communications withvarious modulation schemes. This data may then be relayed from the USVto the HSV. As noted above, a USV may store data received from an AUV,e.g., for later (non-real time) transmission to an HSV.

In order to transmit this data via the ACS, the AUV/USV combinations mayemploy one or more of the modulation schemes listed below, FrequencyShift Keying (FSK), Phase Shift Keying (PSK), Frequency Hopped SpreadSpectrum (FHSS), Direct Sequence Spread Spectrum (DSSS), Frequency andPulse-position modulation (FPPM and PPM), Multiple Frequency ShiftKeying (MFSK), and Orthogonal Frequency-Division Multiplexing (OFDM).

Note that other modulations schemes or other ways to transmit the datamay also be used

In addition, vector sensor communication systems such as single-inputmultiple-output (SIMO) and/or multiple-input multiple-output (MIMO)systems may be employed.

Real Time

Those of ordinary skill in the art will realize and understand, uponreading this description, that, as used herein, the term “real time”means near real time or sufficiently real time. It should be appreciatedthat there are inherent delays in communication/control systems (e.g.,based on distances), and these delays may cause delays in data reachingvarious system components. Inherent delays in the system do not changethe real time nature of the data. In some cases, the term “real timedata” may refer to data obtained in sufficient time to make the datauseful for its intended purpose (e.g., control). Although the term “realtime” has been used here, it should be appreciated that the system isnot limited by this term or by how much time is actually taken for datato have an effect on control information.

Thus are described systems and methods for underwater exploration.

In summary, in some aspects, exemplary embodiments provide a system forexploration of an underwater region.

Below, various exemplary embodiments will be discussed. The systemembodiments are identified by the letter “S” followed by a number. Whenreference is herein made to system embodiments, these embodiments aremeant. Method embodiments are identified by the letter “M” followed by anumber, and when reference is herein made to method embodiments, theseembodiments are meant. Those of ordinary skill in the art willappreciate and understand, upon reading this description, that the scopehereof is not limited by the exemplary embodiments listed below.

Embodiment S1. A system for exploration of an underwater region, thesystem comprising:

-   -   a host platform,    -   multiple surface vehicles (SVs); and    -   multiple autonomous underwater vehicles (AUVs),        -   wherein the host platform and the SVs communicate via a            first communications protocol, and        -   wherein the SVs and the AUVs communicate via a second            communications protocol, distinct from the first            communications protocol, and wherein the host platform            communicates with the AUVs via the SVs, and        -   wherein the multiple AUVs perform aspects of the underwater            exploration simultaneously.

Embodiment S2 comprises: a system according to the preceding embodiment,wherein the first communications protocol comprises one or more of:radio frequency (RF), microwave, IP-based radio, and opticalcommunication signals.

Embodiment(s) S3 comprise: a system according to any of the precedingembodiment(s), wherein the second communications protocol comprises oneor more of: acoustic communication and optical communication.

Embodiment(s) S4 comprise: a system according to any of the precedingembodiment(s), wherein the exploration of the underwater regiondetermines information about the underwater region.

Embodiment(s) S5 comprise: a system according to any of the precedingembodiment(s), wherein the information about the underwater regioncomprises one or more of: mapping data of the underwater region;information about objects in the underwater region; physical and/orchemical oceanographic data of the underwater region; and informationabout objects in or around the underwater region.

Embodiment(s) S6 comprise: a system according to any of the precedingembodiment(s), wherein the host platform comprises a host surfacevehicle (HSV).

Embodiment(s) S7 comprise: a system according to any of the precedingembodiment(s), wherein the number of SVs is the same as the number ofAUVs.

Embodiment(s) S8 comprise: a system according to any of the precedingembodiment(s), wherein each of the SVs is paired with a correspondingone of the AUVs.

Embodiment(s) S9 comprise: a system according to any of the precedingembodiment(s), wherein each AUV communicates via the secondcommunications protocol with the AUV's paired SV, and wherein each SVcommunicates via the first communications protocol with the hostplatform.

Embodiment(s) S10 comprise: a system according to any of the precedingembodiment(s), wherein each AUV sends certain data to the host platform,via an SV paired with the AUV, the certain data representing one or moreof: (i) information about the underwater region, and (ii) informationabout the AUV.

Embodiment(s) S11 comprise: a system according to any of the precedingembodiment(s), wherein the host platform sends control and command datato each AUV via an SV paired with the AUV.

Embodiment(s) S12 comprise: a system according to any of the precedingembodiment(s), wherein a particular SV acts as a relay between (i) thehost platform, and (ii) a particular AUV paired with the particular SV.

Embodiment(s) S13 comprise: a system according to any of the precedingembodiment(s), wherein the particular SV relays the control and commanddata to the particular AUV in real time.

Embodiment(s) S14 comprise: a system according to any of the precedingembodiment(s), wherein at least some of the SVs are in relatively fixedlocations.

Embodiment(s) S15 comprise: a system according to any of the precedingembodiment(s), wherein the number of SVs is greater than the number ofAUVs.

Embodiment(s) S16 comprise: a system according to any of the precedingembodiment(s), wherein the multiple SVs comprise a network of SVs, andwherein the host platform communicates with the AUVs via the network ofSVs.

Embodiment(s) S17 comprise: a system according to any of the precedingembodiment(s), wherein SVs in the network of SVs communicate via a thirdcommunication protocol.

Embodiment(s) S18 comprise: a system according to any of the precedingembodiment(s), wherein the third communications protocol comprises oneor more of: radio frequency (RF), microwave, IP-based radio, and opticalcommunication signals.

Embodiment(s) S19 comprise: a system according to any of the precedingembodiment(s), wherein the third communications protocol is distinctfrom the first communications protocol.

Embodiment(s) S20 comprise: a system according to any of the precedingembodiment(s), wherein the host platform communicates with a first atleast one SV in a network of SVs, and wherein the first at least one SVacts as a relay between (i) the host platform, and (ii) a second atleast one SV in the network of SVs.

Embodiment(s) 21 comprise: a system according to any of the precedingembodiment(s), wherein the second at least one SV in the network of SVsis paired with at least one particular AUV, and wherein the hostplatform communicates with the particular AUV via the first at least oneSV and the second at least one SV.

Embodiment(s) S22 comprise: a system according to any of the precedingembodiment(s), wherein the host platform communicates with the first atleast one SV via the first communications protocol, wherein the first atleast one SV communicates with the second at least one SV via the thirdcommunications protocol, and wherein the second at least one SVcommunicates with the at least one particular AUV via the secondcommunications protocol.

Embodiment(s) S23 comprise: a system according to any of the precedingembodiment(s), wherein the host platform and at least one SV of themultiple SVs communicate directly via the first communications protocol.

Embodiment(s) S24 comprise: a system according to any of the precedingembodiment(s), wherein at least one SV of the multiple SVs and at leastone AUV of the multiple AUVs communicate directly via the secondcommunications protocol.

Embodiment(s) S25 comprise: a system according to any of the precedingembodiment(s), further comprising: at least one mission planningmechanism.

Embodiment(s) S26 comprise: a system according to any of the precedingembodiment(s), wherein the mission planning mechanism defines anddelineates areas to be explored and provides control and commandinformation to at least one AUV of the multiple AUVs for exploration ofthe areas to be explored.

Embodiment(s) S27 comprise: a system according to any of the precedingembodiment(s), wherein the mission planning mechanism provides a searchscheme for the areas to be explored.

Embodiment(s) S28 comprise: a system according to any of the precedingembodiment(s), wherein the mission planning mechanism determines aspectsof the search scheme.

Embodiment(s) S29 comprise: a system according to any of the precedingembodiment(s), wherein the HSV is a ship.

Embodiment(s) S30 comprise: a system according to any of the precedingembodiment(s), wherein aspects of the exploration comprisesimultaneously scanning portions of the underwater region with themultiple AUVs.

Embodiment(s) S31 comprise: a system according to any of the precedingembodiment(s), wherein the multiple SVs comprises at least one unmannedsurface vehicle (USV).

Embodiment(s) M1 comprise: a method of exploring an underwater regionusing the system of any one of the system embodiments (S1-S31).

As used herein, including in the claims, the phrase “at least some”means “one or more,” and includes the case of only one. Thus, e.g., thephrase “at least some ABCs” means “one or more ABCs”, and includes thecase of only one ABC.

As used in this description, the term “portion” means some or all. So,for example, “A portion of X” may include some of “X” or all of “X”. Inthe context of a conversation, the term “portion” means some or all ofthe conversation.

As used herein, including in the claims, the phrase “based on” means“based in part on” or “based, at least in part, on,” and is notexclusive. Thus, e.g., the phrase “based on factor X” means “based inpart on factor X” or “based, at least in part, on factor X.” Unlessspecifically stated by use of the word “only”, the phrase “based on X”does not mean “based only on X.”

As used herein, including in the claims, the phrase “using” means “usingat least,” and is not exclusive. Thus, e.g., the phrase “using X” means“using at least X.” Unless specifically stated by use of the word“only”, the phrase “using X” does not mean “using only X.”

In general, as used herein, including in the claims, unless the word“only” is specifically used in a phrase, it should not be read into thatphrase.

As used herein, including in the claims, the phrase “distinct” means “atleast partially distinct.” Unless specifically stated, distinct does notmean fully distinct. Thus, e.g., the phrase, “X is distinct from Y”means that “X is at least partially distinct from Y,” and does not meanthat “X is fully distinct from Y.” Thus, as used herein, including inthe claims, the phrase “X is distinct from Y” means that X differs fromY in at least some way.

It should be appreciated that the words “first” and “second” in thedescription and claims are used to distinguish or identify, and not toshow a serial or numerical limitation. Similarly, the use of letter ornumerical labels (such as “(a)”, “(b)”, and the like) are used to helpdistinguish and/or identify, and not to show any serial or numericallimitation or ordering.

No ordering is implied by any of the labeled boxes in any of the flowdiagrams unless specifically shown and stated. When disconnected boxesare shown in a diagram, the activities associated with those boxes maybe performed in any order, including fully or partially in parallel.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1. A system for exploration of an underwater region, the systemcomprising: a host platform comprising a host surface vehicle (HSV);multiple surface vehicles (SVs); and multiple autonomous underwatervehicles (AUVs), wherein the host platform and the surface vehiclescommunicate via a first communications protocol, and wherein the surfacevehicles and the AUVs communicate via a second is communicationsprotocol, distinct from said first communications protocol, and whereinsaid host platform communicates with said AUVs via said surfacevehicles, and wherein said multiple AUVs perform aspects of saidunderwater exploration simultaneously, and wherein at least one AUVperforms aspects of said exploration independent of at least one otherAUV, and wherein the multiple SVs comprise a network of surfacevehicles, and wherein said host platform communicates with said AUVs viasaid network of surface vehicles, and wherein surface vehicles in saidnetwork of surface vehicles communicate via a third communicationprotocol, wherein the host platform communicates with a first at leastone SV in a network of SVs, and wherein the first at least one SV actsas a relay between (i) the host platform, and (ii) a second at least oneSV in the network of surface vehicles, wherein at least one missionplanning mechanism defines and delineates at least one area to beexplored and provides control and command information to at least oneAUV of said multiple AUVs for exploration of said at least one area tobe explored.
 2. The system of claim 1 wherein said first communicationsprotocol comprises one or more of: radio frequency (RF), microwave,IP-based radio, and optical communication signals.
 3. The system ofclaim 1, wherein said second communications protocol comprises one ormore of: acoustic communication and optical communication.
 4. The systemof claim 1, wherein said exploration of said underwater regiondetermines information about said underwater region.
 5. The system ofclaim 4, wherein said information about said underwater region comprisesone or more of: (i) mapping data of said underwater region; and/or (ii)information about objects in said underwater region; and/or (iii)physical and/or chemical oceanographic data of said underwater region;and/or (iv) information about objects in or around said underwaterregion.
 6. The system of claim 1 wherein the number of surface vehiclesis the same as the number of AUVs.
 7. The system of claim 6 wherein eachof said surface vehicles is paired with a corresponding one of saidAUVs.
 8. The system of claim 7 wherein each AUV communicates via saidsecond communications protocol with said AUV's paired SV, and whereineach SV communicates via said first communications protocol with saidhost platform.
 9. The system of claim 8 wherein each AUV sends certaindata to said host platform, via a surface vehicle paired with said AUV,wherein said certain data represents one or more of: (i) informationabout said underwater region, and/or (ii) information about said AUV.10. The system of claim 8 wherein the host platform sends control and/orcommand data to each AUV via an SV paired with said AUV.
 11. The systemof claim 9 wherein a particular SV acts as a relay between (i) said hostplatform, and (ii) a particular AUV paired with said particular SV. 12.The system of claim 11 wherein said particular SV relays said controland command data to said particular AUV in real time.
 13. The system ofclaim 1 wherein at least some of said SVs are in relatively fixedlocations.
 14. The system of claim 1, wherein the number of SVs isgreater than the number of AUVs.
 15. The system of claim 1, wherein saidthird communications protocol comprises one or more of: radio frequency(RF), microwave, IP-based radio, and/or optical communication signals.16. The system of claim 1, wherein said third is communications protocolis distinct from said first communications protocol.
 17. The systemaccording to claim 1, wherein the second at least one SV in the networkof SVs is paired with at least one particular AUV, and wherein the hostplatform communicates with the particular AUV via the first at least oneany of the and second at least one SV.
 18. The system according to claim17, wherein the host platform communicates with the first at least oneSV via the first communications protocol, wherein the first at least oneSV communicates with the second at least one SV via the thirdcommunications protocol, and wherein the second at least one SVcommunicates with the at least one particular AUV via the secondcommunications protocol.
 19. The system of claim 1, wherein the hostplatform and at least one SV of said multiple SVs communicate directlyvia said first communications protocol.
 20. The system of claim 1,wherein at least one SV of said multiple SVs and at least one AUV ofsaid multiple AUVs communicate directly io via the second communicationsprotocol.
 21. (canceled)
 22. (canceled)
 23. The system of claim 1,wherein said at least one mission planning mechanism provides a searchscheme for said at least one area to be explored.
 24. The system ofclaim 23 wherein said at least one mission planning mechanism determinesaspects of said search scheme.
 25. (canceled)
 26. The system of claim 1,wherein aspects of said exploration comprise simultaneously andindependently scanning portions of said underwater region with saidmultiple AUVs.